1. Technical Field
The present invention is directed toward a structure and method for unitizing and bracing loads and, more particularly, toward a collapsible structure and method for unitizing and bracing loads in moving vehicles, such as truck trailers.
2. Background Art
The desirability for unitizing loads during transport is well-known. Glass items, including liquid containers, are particularly susceptible to breaking as a result of being bumped during transport. Further, shifting of massive payloads results in dangerous dynamic instabilities in the motion of a truck trailer. By unitizing loads, the shifting of the loads can be minimized during transport, and therefore damage to parts of the load resulting from bumping, as well as precarious vehicle dynamics, can be reduced.
In addition to payload damage and safety concerns, compliance with truck trailer weight distribution regulations necessitates the use of load-positioning structure. Truck trailers are typically limited, by law, to carry a payload of no greater than 48,000 lbs. This load must be distributed so that neither trailer axle is loaded in excess of 24,000 lbs. In order to maintain the weight distribution of a trailer load during transport, it is important to have the capability of unitizing and fixedly positioning the load.
One method which has been used is to place straps around the load, as shown in U.S. Pat. No. 1,920,917 to Scales. However, the structure disclosed in this patent for unitizing such loads is not readily adaptable to loads of different heights. The straps of such structure bear against the edges of the loads and thereby damage the loads.
Structure to prevent the shifting of a load in a moving vehicle is shown in U.S. Pat. Nos. 4,193,736 to Thomaswick.
Thomaswick discloses a pair of spaced deck runners, with a stanchion and lash bar attached to the runners adjustable along the length thereof. Loads are unitized and confined between the stanchion and lash bar. The Thomaswick structure is complicated and, to be effective, must have runners extending over the entire length of the load-supporting surface to which it is attached. Such a structure takes up valuable space in vehicles and, because of the weight, reduces payload.
Further, the stanchion in Thomaswick takes up a substantial amount of space lengthwise of the runners. In certain situations, it is impossible to incorporate the Thomaswick structure into a vehicle. For example, if the load extends to within approximately two feet of the rear wall of the carrying vehicle, bracing of the load against rearward shifting may be required. The Thomaswick structure would not fit in the allowed space. Further, by reason of the complicated nature of the Thomaswick structure, its manufacture is relatively involved and costly.
Still other structures have been used, such as airbags, to fill the empty spaces in a transport vehicle. However, these structures can be dangerous as they are placed in relatively high pressures and can sometimes force the transport vehicle doors open, striking nearby individuals. Still further, the airbags are expensive and difficult to use.
The present invention is directed toward overcoming one or more of the problems as set forth above.